Properties of Spinel Protective Coatings Prepared Using Wet Powder Spraying for SOFC Interconnects

Tuesday, 28 July 2015: 14:40
Alsh (Scottish Exhibition and Conference Centre)
J. E. Hong (The University of Birmingham), M. Bianco (Ecole Polytechique Fédérale de Lausanne (EPFL)), J. Van herle (Ecole Polytechnique Fédérale de Lausanne (EPFL)), and R. Steinberger-Wilckens (The University of Birmingham)
Manganese cobalt spinel coatings have attracted much interest as a protective layer for stainless steel interconnects of solid oxide fuel cells (SOFCs) owing to their effectiveness of suppressing high temperature oxidation and Cr evaporation. In this study, a simple wet powder spraying (WPS) method was applied to prepare spinel layers on commercial stainless steels (Sanergy HT and K41/441) which were evaluated as protective coating of SOFC interconnects. A condition of heat treatment on spray coatings was optimised to achieve dense protective layers with microstructure analysis. Area specific resistance (ASR) and stability were measured in a humid atmosphere at 700 °C for 1000 hours. Post-test analysis was conducted on microstructure of measured samples using SEM-EDS. In addition, effect of a sublayer with spinel coatings was investigated on ASR and Cr retention. The implication for microstructure, ASR and stability of the evaluated coatings is discussed.